The present exemplary embodiments relate to a printer apparatus or the like, and more particularly, to printing on tab stock, i.e., heavy weight media or sheets having an irregular, protruding portion on one edge thereof, with such a printer.
Duplex printing of tab stock requires feeding the tab stock with the tab edge leading from through the registration transport. This requirement is incompatible with machines using stalled roll deskew registration as shown, for example in U.S. Pat. Nos. 3,949,979 and 4,128,327. No provision is made in the systems of these patents for providing deskew of tab stock.
Other existing printing products can print tabs in duplex mode by using an edge registration system, i.e. the sheets are biased against their top or bottom edge using a cross-roll or other edge registration system.
While still other systems are limited to printing tab sheets in simplex mode only; such as, for example where two sensors are used to detect lead edge skew and an electronic (or differential drive) mechanism is used to deskew the sheets. If the tabbed sheets were inverted for printing on side two, the tab would be on the leading edge of the sheet which would create problems when the lead edge passed the two skew sensors. Also, since only two point sensors are used, and they must be located to detect the smallest size media handled by the system, the accuracy of the skew reading is compromised when the larger baseline media is being used.
Accordingly, disclosed herein is a printer including a registration media sensing system that can handle tabbed sheets, even with the tab leading (on the leading edge). The system makes use of multiple sensors, for example point sensors, to detect the presence of a tab and to determine the lead edge skew of the sheet.
The disclosed apparatus may be readily operated and controlled in a conventional manner with known or conventional copier or printer control systems, operated as taught herein. Some additional examples of various prior art copiers with document handlers and control systems therefore, including sheet detecting switches, sensors, etc., are disclosed in U.S. Pat. Nos. 4,054,380; 4,062,061; 4,076,408; 4,078,787; 4,099,860; 4,125,325; 4,132,401; 4,144,550; 4,158,500; 4,176,945; 4,179,215; 4,229,101; 4,278,344; and 4,475,156. It is well known in general and preferable to program and execute such control functions and logic with known software instructions for known microprocessors. This is taught by the above and other patents and various commercial copiers. Such software may of course vary depending on the particular function and the particular software system and the particular microprocessor or microcomputer system being utilized, but will be available to or readily programmable by those skilled in the applicable arts without undue experimentation from either verbal functional descriptions, such as those provided herein, or prior knowledge of those functions which are conventional, together with general knowledge in the software and computer arts. Controls may alternatively be provided utilizing various other known or suitable hard-wired logic or switching systems.
As shown in the above-cited art, the control of exemplary document and copy sheet handling systems in copiers or printers may be accomplished by conventionally actuating them by signals from the copier controller directly or indirectly in response to simple programmed commands and from selected actuation or non-actuation of conventional copier switch inputs by the copier operator, such as switches selecting the number of copies to be made in that run, selecting simplex or duplex copying, selecting whether the documents are simplex or duplex, selecting a copy sheet supply tray, etc. The operator inputs and controls, and machine internal controls or limits, may be coordinated and/or made interactive with operator displays and “prompts” or instructions; e.g., U.S. Pat. No. 4,332,464 issued Jun. 1, 1982 regarding the Xerox Corporation “5700” printer. The resultant controller signals may conventionally actuate various conventional electrical solenoid or cam-control led sheet deflector fingers, motors or clutches in the copier in the selected steps or sequences as programmed. Conventional sheet path sensors, switches and bail bars, connected to the controller, may be utilized for sensing and timing the positions of documents and copy sheets, as is well known in the art, and taught in the above and other patents and products. Known copying systems utilize such conventional microprocessor control circuitry with such connecting switches and sensors for counting and comparing the numbers of document and copy sheets as they are fed and circulated, keeping track of their general positions, counting the number of completed document set circulations and completed copies, etc. and thereby controlling the operation of the document and copy sheet feeders and inverters, etc.
All references cited in this specification, and their references, are incorporated by reference herein where appropriate for appropriate teachings of additional or alternative details, features, and/or technical background.
Various of the above-mentioned and further features and advantages will be apparent from the specific apparatus and its operation described in the example(s) below, as well as the claims. Thus, the present exemplary embodiments will be better understood from this description of an embodiment thereof, including the drawing figures.